corndog71 wrote:Tube amps have been around for over 80 years. The vast majority never needed heat sinks. Even when they were inside wooden box radios, TV consoles, or with perforated sheet metal cages around them.

corndog71 wrote:Tube amps have been around for over 80 years. The vast majority never needed heat sinks. Even when they were inside wooden box radios, TV consoles, or with perforated sheet metal cages around them.

Seriously. Not needed.

Fleming created a practical vacuum tube in 1904 used for amplification of small signals. The 200-family of vacuum tubes came about in 1924, and was used for actual speakers of the day, as well as rF amplification.

So, properly, 115 years for the concept and initial application.95 years for widespread practical consumer/commercial applications.

This year, my oldest radio officially becomes an "antique" achieving 100 years in age. Works, too.